This invention relates generally to adhering silicon nitride films to carbon-containing silicon oxide films.
In interconnect systems, it is desirable to integrate low dielectric constant interlayer dielectric carbon doped oxide films. Carbon doping of the oxide improves the overall performance of the interconnect system by lowering its dielectric constant. However, the carbon doping also degrades the interface adhesion between the carbon doped oxide interlayer dielectric films and silicon nitride etch-stop films. As a result of the poor adhesion, thermomechanical failures may occur due to packaging induced stress. These failures may occur at the top and bottom of the carbon doped oxide films.
Current techniques for solving this problem involve using a downstream plasma ammonia pretreatment of the carbon doped oxide film surface before the silicon nitride film deposition. However, this treatment merely removes surface contaminants and does not reduce or solve the adhesion problem.
Thus, there is a need for better ways to adhere silicon nitride films to carbon-doped oxide films.